web-mode-column-show in web-mode.el to display a column that "connects" the start tag and the end tag.
This column may cross empty lines. In that case I use
(move-to-column COL t) (see the
t arg) to put the overlay at the right column. The problem is that, doing so, I modify the buffer content (I add spaces).
Is there a way to display an overlay at a specific line/column where no "content" exists ?